The present invention relates to a new and improved construction of a drive system for marine vessels containing two or more drive units or machines, especially gas turbines, two or more propellers and gearing which interconnects the propellers with one another and contains drive pinions which can be coupled, by means of a respective switchable clutch, with a respective one of the drive units.
Coastguard vessels and certain warships, such as frigates, equipped with two or more drive units or machines and two or more propellers, must be capable, on the one hand, during cruising travel, of driving both propellers by means of only one of the drive units and, on the other hand, when confronted with special situations or conditions, for instance during battle, must be capable of utilizing the completely available drive output of both or all of the drive units or machines. In this regard there must exist the possibility, during rapid change of the direction of travel, of adjusting the vanes of a propeller such that its power consumption is almost null and the totally available drive power or output is transmitted to any other selected propeller, for instance a propeller whose vanes have been set to have a correspondingly large pitch.
With a state-of-the-art drive system of the previously disclosed type, for instance as taught in British Pat. No.
1,120,941, especially FIGS. 3 and 4, two primary drive machines can be coupled, by means of a respective switchable clutch, with a respective drive pinion. These drive pinions drive, by means of a respective gear of a first gearing stage and a respective pinion fixedly connected therewith of a second gearing stage, a respective gear of the second gearing stage. The gears of the second gearing stage are connected, on the one hand, with a respective propeller and, on the other hand, by means of an intermediate gear and an intermediate pinion meshing therewith, with one another. The intermediate pinion is coupled by means of a third switchable clutch with an auxiliary drive machine. When both of the primary drive machines or units are operative, it can happen that one of them delivers power, by means of the closest situated gear of the second gearing stage, only to the therewith connected propeller, whereas the other primary drive machine likewise delivers power, by means of the closest situated gear of the second gearing stage, exclusively to the related second propeller. During the declutched condition of the auxiliary drive machine the intermediate pinion and the intermediate gear do not participate in the transmission of any drive power, rather only are loaded by torque fluctuations which randomly arise at the propellers. Owing to the unavoidable play between the unloaded tooth flanks it is possible for oscillations to arise at the prior art drive system, these oscillations no longer being controllable and can lead to undesired destruction of parts of the gearing system. It is even possible for loads to arise at the heretofore known drive systems, which the individual gear components only then can withstand if they are designed and dimensioned to be stronger than for taking-up the loads contemplated to be encountered during normal operation, if there occurs a sudden change in course with the full output of both primary drive machines in that one of the propellers is set for taking-up as little power as possible and the other is set for taking-up the maximum amount of power.